Table 3.

Baroreflex sensitivity during whole body heating

	Normothermia	Mild Heating	Heat Stress	P
CHF patients
BRS BI	−1.26 ± 0.31‡§	−1.27 ± 0.28‡	−1.38 ± 0.39‡	0.758
BRS Area	−0.150 ± 0.070	−0.421 ± 0.099	−0.308 ± 0.090	0.139
BRS total	−0.352 ± 0.068	−0.418 ± 0.060	−0.504 ± 0.099	0.377
BRS RRI	7.2 ± 1.8‡§	8.7 ± 2.8	4.3 ± 1.2‡	0.076
Age-matched healthy subjects
BRS BI	−2.74 ± 0.57	−2.05 ± 0.39	−2.27 ± 0.27	0.045
BRS Area	−0.327 ± 0.075	−0.241 ± 0.041	−0.182 ± 0.105	0.257
BRS total	−0.678 ± 0.106	−0.461 ± 0.064	−0.502 ± 0.046	0.081
BRS RRI	13.5 ± 1.6	8.9 ± 1.5*	7.7 ± 1.3*	0.001
Young healthy subjects
BRS BI	−2.43 ± 0.32	−2.85 ± 0.54	−3.07 ± 0.24*	0.045
BRS Area	−0.657 ± 0.173	−0.660 ± 0.134	−0.457 ± 0.273	0.257
BRS total	−0.455 ± 0.063	−0.671 ± 0.156	−0.560 ± 0.136	0.395
BRS RRI	23.6 ± 2.8	15.5 ± 2.0*	13.1 ± 1.9*	0.001

Values are means ± SE. Units for the baroreflex sensitivity (BRS) indices: muscle sympathetic nerve activity (MSNA) burst incidence (BRS BI), bursts·100 beats⁻¹·mmHg⁻¹; MSNA burst area (BRS area), U·burst⁻¹·mmHg⁻¹; MSNA total activity (BRS total), U·beats⁻¹·mmHg⁻¹; cardiac interval (BRS RRI), ms/mmHg.

^*P < 0.05 vs. normothermia.

^‡P < 0.05 vs. young control subjects under the respective thermal condition.

^§P < 0.05 vs. age-matched control subjects under the respective thermal condition.